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Process for preparing silica microcapsules

a technology of silica and microcapsules, applied in the field of process for preparing silica microcapsules, can solve the problems of skin troubles, deterioration of cosmetics quality, poor chemical stability properties, etc., and achieve the effect of reducing environmental pollution

Inactive Publication Date: 2005-02-15
UNITECH CO LTD (JP)
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

The present invention was completed by preparing a precursor composite to have a hydrophilic or lipophilic character, adding a core material and an appropriate amount of aminopropyltrialkoxysilane as a gelling agent therein, and emulsifying and dispersing into a solution having a polarity opposite to that of the core material and containing a small amount of a surfactant to encapsulate the core material with silica shell by a sol-gel reaction. The process of the present invention obviously reduces environmental pollution as compared to the conventional process that uses an ammonia solution as a basic gelling agent and is also suitable for both hydrophilic and lipophilic core materials.

Problems solved by technology

However, when a large amount of a UV absorbing agent is added to improve SPF values, it may cause skin troubles and deteriorate quality of cosmetics.
Since the polymer shell materials have poor properties in chemical stability, heat resistance and strength, their usages are often limited depending on their intended purposes.
This method simultaneously encapsulates a core material as a method for encapsulating by organic polymers but requires a large amount of a surfactant to reduce the size of capsules that then causes difficulty in removing the surfactant.
Further, this method is not suitable for water-soluble core materials.
This process may cost extra labor and expense, and further, use of a basic catalyst may be limited by the treatment regulation.

Method used

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  • Process for preparing silica microcapsules
  • Process for preparing silica microcapsules
  • Process for preparing silica microcapsules

Examples

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example 1

Of tetraethoxy orthosilicate(TEOS) 1160 g, first 160 g was slowly added to 0.01M aqueous solution of HCl 100 g for 3 hours and the remaining 1000 g was added for 1 hour. The reaction mixture was stirred for 12 hours to obtain a clear solution. The clear solution was evaporated under the pressure at a temperature of 50° C. to remove ethanol produced as a byproduct during the reaction. The resulting solution was a clear viscous precursor solution for lipophilic core material of which viscosity was about 35 cp and molecular weight was 3,200 Mw determined using gel permeation chromatography (GPC). 20 parts by weight of octylmethoxycinnamate as a core material was dissolved in the lipophilic precursor solution. 1.0 part by weight of aminopropyltriepoxysilane(APS) as an inner gelling agent was added into the resulting solution to produce emulsion solution. While an aqueous solution containing 1.0 part by weight of a surfactant (Triton X-100) in a separate container was stirred at a rate o...

example 2

Of tetraethoxy orthosilicate(TEOS) 7760 g, first 170 g was slowly added to 0.01M aqueous solution of HCl 100 g for 3 hours and the remaining 600 g was added for 1 hour. The reaction mixture was stirred for 12 hours to obtain a clear solution. The clear solution was evaporated under the pressure at a temperature of 50° C. to remove ethanol produced as a byproduct during the reaction. The resulting solution was a clear viscous precursor solution for hydrophilic core material of which viscosity was about 935 cp and molecular weight was 5,500 Mw determined using gel permeation chromatography (GPC). 20 parts by weight of 4-hydroxybenzophenone as a core material was dissolved in the hydrophilic precursor solution. 0.5 parts by weight of aminopropyltriepoxysilane(APS) as an inner gelling agent was added into the resulting solution to produce emulsion solution. While cyclohexene containing 1.5 parts by weight of a surfactant(Triton X-100) in a separate container was stirred at a rate of abo...

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Abstract

The present invention relates to a process for preparing silica microcapsules and more particularly, to a process for preparing silica microcapsules comprising the steps of dissolving tetraethyl orthosilicate (TEOS) into an aqueous solution containing a hydrolysis catalyst to control a degree of hydrolysis and contribute hydrophilicity or lipophilicity, adding a core material and an appropriate amount of aminopropyltrialkoxysilane(APS) as a gelling agent into the solution, and emulsifying and dispersing the resulting solution to a solution having a polarity opposite to that of the core material to microcapsulate by coating the core material with silica shell via a sol-gel reaction. The process for preparing microcapsules of the present invention reduces environmental pollution compared to conventional processes using an alkali gelling agent such as an ammonia solution, and are suitable for both organic or inorganic core materials having hydrophilic or lipophilic property.

Description

FIELD OF THE INVENTIONThe present invention relates to a process for preparing silica microcapsules, and more particularly, to a process for preparing silica microcapsules comprising the steps of dissolving tetraethyl orthosilicate (TEOS) into an aqueous solution containing a hydrolysis catalyst to control a degree of hydrolysis and contribute hydrophilicity or lipophilicity, adding a core material and an appropriate amount of aminopropyltrialkoxysilane(APS) as a gelling agent into the solution, and emulsifying and dispersing the resulting solution to a solution having a polarity opposite to that of the core material to encapsulate the core material with silica shell via a sol-gel reaction. The process for preparing microcapsules of the present invention is more excellent in reducing environmental pollution as compared to conventional processes, which use an alkali gelling agent such as an ammonia solution, and is suitable for organic or inorganic core materials having hydrophilic o...

Claims

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Application Information

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IPC IPC(8): B01J13/02A61K9/32C08J3/12
CPCB01J13/02Y10T428/2985Y10T428/2991Y10T428/2989Y10T428/2998C08J3/12
Inventor SEOK, SANG ILAHN, BOK YEOP
Owner UNITECH CO LTD (JP)
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